Silver halide developing agents and photographic process

ABSTRACT

Photographic process and product employing silver halide developing agents of quaternary ammonium compounds of the formula:

I United States Patent 3,590,692

[72] Inventor Slanle) M. Bloom. 3,345,166 10/1967 Land et a1 96/29 A INo yagss Primary Examiner-William D. Martin zz y I968 AssistantExaminer-Theodore G. Davis Atlorneys-Brown and Mikulka, Stanley H.Mervis and Mark [45] Patented July 6, 1971 C Jacobs [73] AssigneePolaroid Corporation Cambridge, Mass.

ABSTRACT: Photographic process and product employing silver halidedeveloping agents of quaternary ammonium com- [54] SILVER HALIDEDEVELOPING AGENTS AND pounds of h f l PHOTOGRAPHIC PROCESS 8 Claims, NoDrawings P LINK QUAT. wherein DEV 18 a dihydroxyaryl silver halidedeveloplng radi- [52] US. Cl 92/26, l or a di lkox aryl ordialkoxymethoxyaryl precursor 96/53, 96/ 16 thereof; LINK is ahydrocarbon radical of at least 2 and [5 i ll"- v t t 1 preferably 3carbon atoms or a hydrocarbon radical preceded G039 5/ 54 by and/orinterrupted by individual atoms of oxygen or sulfur [50] Field of Search96/29, 63, with the proviso that an interrupting atom f oxygen or m 76,95 cannot be closer than two carbon atoms away in the chain from theositivel char ed nitro en atom of the uaternar [561 Remems ammoniu lradicai QUA T bonde m LINK throug it the pen UMTED STATES PATENTStavalent nitrogen atom. The preferred mode of preparation of 3,196,0157/1965 Ryan 96/29 these compounds is by the alkylation of an amine.These com- 3,232,758 2/1966 Holstead et a1 96/29 pounds are especiallyuseful in photography as silver halide 3,326,683 6/1967 Land et a].96/29 developing agents.

PATENTEU JUL 6 I97! Fig.2

SHEET 1 [1F 2 INVENTOR BY ?(r z-JM ATTORNEYS PATENTEU JUL 6 |97| SHEET 20F 2 INVENTOR ATTORNEYB I OH are good silver halide developing agents.The introduction of positive substituents such as CH and -OCH onto thehydroquinone nucleus of such derivatives increases the developmentcapability of such compounds whereas the introduction of negativesubstituents decreases it. The positive charge of the pyridinium groupmight be expected to weaken the developing agent by the withdrawal ofelectrons from the hydroquinone system. The positive charge on thepyridinium group would be expected to make it easier for thehydroquinone ion to penetrate the negative charge barrier surroundingthe silve halide grains, and this action may more than offset theelectron withdrawal effect.

When such developing agents were utilized in diffusion transferprocessing compositions which, as is known in the art, have a high pH ofabout 13, it was found that the developing agent fragmented. It has nowbeen found that if a linking group containing at least two andpreferably three carbon atoms is present between the positively chargednitrogen atom and the hydroquinone radical, or at least two carbon atomsbetween the positively charged nitrogen atom and any other atoms, suchas oxygen or sulfur atoms, comprising a part of said linking group thatsuch fragmentation will not occur. The utilization of the linking groupalso overcomes any electron withdrawing effect attributed to thequaternary nitrogen atom while still maintaining the benefits to bederived from the positive charge in regard to the penetration of thenegative charge barrier.

Accordingly, it is one object of the present invention to provide novelquaternary ammonium compounds which are alkali stable silver halidedeveloping agents suitable for use in diffusion transfer processes.

Another object is to provide novel processes and processing compositionsfor forming images by a diffusion transfer process wherein the novelcompounds are utilized as the silver halide developing agent.

Still another object is to provide procedures for the preparation of thenovel compounds.

Other objects of this invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the processes involving the severalsteps and the relation and order of one or more of such steps withrespect to each of the others, and the products and compositionspossessing the features, properties and the relation of elements whichare exemplified in the following detailed disclosure, and the scope ofthe application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description.

The novel compounds of this invention may be represented by the formula:

(2) DEVLlNK--QUAT wherein DEV is a dihydroxyaryl silver halidedeveloping radical; or a dialkoxyaryl or dialkoxymethoxy precursorthereof, or a monoamine monohydroxy silver halide developing radical; ora nitroalkoxyaryl or nitroalkoxymethoxyaryl precursor thereof; LINK is adivalent organic radical bonded to a nuclear carbon atom of DEV and toQUAT through a pentavalent nitrogen atom of QUAT, wherein the atom ofLINK next adjacent to DEV is selected from among oxygen, sulfur andcarbon, the remainder of said radical being a linear two to nine carbonatom hydrocarbon chain or a hydrocarbon chain which is interrupted byindividual oxygen or sulfur atoms, with the proviso that an interruptingatom of oxygen or sulfur is not bonded to the carbon atom of LINK bondedto said pentavalent nitrogen atom of QUAT, and QUAT is a cyclic oracyclic quaternary ammonium radical which is bonded through thepentavalent nitrogen atom thereof to LINK and which radical when acyclichas three of its valences filled by three unsubstituted or halogensubstituted hydrocarbon groups, and which radical when entirely cycliccomprises a heterocyclic ring which fills three of its valences, andwhich radical when partially cyclic and partially acyclic, contains anacyclic unsubstituted or halogen substituted hydrocarbon group to fillone valence, two other valences being filled by a heterocyclic ring,said rings containing in addition to the nitrogen atom bonded to theLINK --radical, carbon atoms, hydrogen atoms and optionally an atomselected from the group consisting of nitrogen, oxygen, selenium andsulfur.

As noted above, it has unexpectedly been discovered that thesedihydroxyaryl containing developing agents are stable in highconcentrations of alkali and as such can be utilized in diffusiontransfer processing compositions, which as is known in the art, aregenerally of the pH of about 13 or more. This is surprising in view ofthe fact that compounds of the formula:

wherein DEV is a dihydroxyaryl silver halide developing radical; R R R Rand R are hydrocarbon substituents and M comprises the atoms necessaryto complete a heterocyclic ring, when placed in strongly alkaline media,liberate the pertinent amine compound. This liberation is easilyattested to as, for instance, by the smell of pyridine being liberatedfrom an alkaline solution of the compound:

l O H The novel compounds of this invention for ease and simplicity maybe represented by the formula:

(3) LA,RD wherein L is an unsubstituted, alkylsubstituted or halogensubstituted monovalent radical selected from the group consisting ofphenyl and naphthyl rings substituted in ortho or para positions withrespect to each other by 7 H and --NH,, at least one ofsaid positionsbeing substituted by -OH or the precursors thereof, wherein theprecursor group for -OH is an alkoxy or alkoxymethoxy group. and theprecursor for NH is -NO,,

A is selected from the group consisting of oxygen and sulfur. e is l or0', R is a divalent radical of the formula. 2l 2 -tlm' l 2ln 2 2[ 2 4lml 2]n 2 wherein m is a number from 0 to 4 inclusive; n is a number fromO to 8 inclusive; the sum of m-l-n being not greater than 8;

D is a cyclic, acyclic, or part cyclic part acyclic quaternary ammoniumradical selected from the group of radicals of the formulas:

wherein each 0 and T are acyclic hydrocarbon or halogen substitutedhydrocarbon groups, M represents the atoms necessary to complete aheterocyclic ring and contains in addition to carbon and hydrogen atoms,optionally an atom selected from the group consisting of nitrogen,oxygen, sulfur and selenium, and X is an anion whose presence isnecessary to balance the positive charge of the pentavalent nitrogensuch as halide, methyl sulfonate, and p-toluene sulfonate.

As has been indicated, the compounds of this invention are within theformula:

(3) L A, R -D L, as has been indicated is an ortho or para dihydroxybisalkoxy or bisalkoxymethoxyaryl radical.

As examples of useful dihydroxyphenyl radicals comprising L"substituents, mention may be made of orthodihydroxyphenyl,paradihydroxyphenyl and nuclear-substituted derivatives thereof, e.g.,chloro, methyl, phenyl, and/or methoxysubstituted derivatives thereof,particularly nuclear-substituted p-dihydroxphenyls such asmethylhydroquinonyl, pmethylphenylhydroquinonyl, chlorohydroquinonyl,methoxyhydroquinonyl, 2,6-dimethylhydroquinonyl,2,6-dimethoxyhydroquinonyl, 2-methoxy-G-methylhydroquinonyl, 2,3-dimethylhydroquinonyl, 2,5,6,-trimethylhydroquinonyl, etc.

As examples of useful dihydroxynaphthyl silver halide developingradicals comprising L," mention may be made of any of the abovedihydroxyphenyl radicals wherein the benzene ring is replaced by anaphthalene ring and the other substituents are appropriately situated.

As examples of useful dialkoxyaryl and dialkoxymethoxyaryl radicals forthis invention, mention may be made of the above dihydroxyphenylradicals wherein the hydroxyl groups are replaced by alkoxy groupscontaining from one to five carbon atoms, and the aryl ring is either abenzene ring or a naphthalene ring.

As examples of useful nitrogen containing silver halide developingradicals, mention can be made of any of the abovementioned dihydroxyarylradicals wherein one of the hydroxyl groups is replaced by an -NH,group. The precursors for such nitrogen containing developing radicalsare those radicals which contain an NO group ortho or para to thehydroxyl precursor group. As examples of such nitroalkoxyaryl andnitroalkoxymethoxyaryl radicals, mention may be made of 2-nitro,S-ethoxy benzene and any of the dihydroxyaryl radicals above wherein onehydroxyl group is replaced by a nitro group and the other hydroxyl groupis replaced by an alkoxy or alkoxymethoxy group.

A,, previously defined. taken together with R comprise the total linkingunit between the silver halide developing radical and the quatemaryammonium radical, D.

As illustrations of suitable alkylene radicals comprehended by R.mention may be made of radicals such as As examples of some hydrocarbonsubstituents containing unsaturation that are suitable as R radicals,mention can be made of radicals such as As examples of R radicalscontaining ether and thioether linkages, mention can be made of Itshould be noted that any R substituent that comprises purely hydrocarbonunits must contain at least two and preferably three carbon atoms in thechain to avoid cleavage of the molecule when it is placed in a stronglyalkaline environment. lf oxygen or sulfur atoms are present in thechain, there should not be an atom of one of these bonded to the samecarbon atom as is bonded to the pentavalent nitrogen atom of D, norshould such an atom be bonded directly to the pentavalent nitrogen atomof D. Here too, the necessity for two carbon atoms between such oxygenor sulfur atoms is to avoid cleavage in an alkaline medium.

D is a quaternary ammonium radical. As is known, quaternary ammoniumcompounds are organic compounds containing a pentavalent nitrogen atom.Generally they can be considered as derivatives of ammonium compoundswherein the four valences usually occupied by the hydrogen atoms areoccupied by organic radicals. Generally the organic radicals are joineddirectly to the pentavalent nitrogen through a single or doublecarbon-to-nitrogen bond. The term quaternary ammonium, as used herein,is intended to cover compounds wherein the pentavalent nitrogen is oneof the nuclear atoms in a heterocyclic ring as well as those whereineach of the four valences is attached to separate organic radicals. Notethe formulas above.

Typical quaternary ammonium radicals include2-picolinium-p-toluenesulfonate, pyridinium bromide, triethylaminechloride, 3-quinolinium bromide, n-methyl piperidinium iodide, trimegachlorobutylamine methyl sulfonate, etc.

While the preferred quaternary ammonium radicals are those where Q, Tand M are all hydrocarbon, it is understood as set forth above thatthese Q, T and M groups can contain other hetero atoms. As such, typicalcyclic quaternary ammonium radicals suitable for use in this inventionwould include those derived from compounds of the thiazole, selenazole,oxazole, imidazole and indole series among others.

In a preferred embodiment of this invention, L is a dihydroxyphenylradical, AR is an alkylene radical of two to 10 carbon atoms inclusive,and D is a quaternary ammonium radical. Such compounds are representedby the formulas wherein z is an integer of from 2 to l inclusive.

Another preferred embodiment comprises compounds wherein L is abisdialkoxyphenyl radical, AR and D are of the significance indicated atformula Such compounds are represented by the formulas Ql HehH l dYwherein z is an integer of from 2 to inclusive, and y is an integer offrom 1 to 5 inclusive.

In the scope of formulas (4) and (5), typical preferred compoundsinclude l-(2', S'clihydroxyphenyl) propyl-3-pyridinipropy1-4-methylquinolinium bromide and N-7(2, S'dimethoxyphenum bromide, N-'y(2',S'-dihydroxyphenyl) yl)butyl-pyridinium tosylate, which are of theformulas:

CH -CHr-CHr-N Br- I OH carom-Curie i411, Br-

I OH

01f -onz-o CH; cur-bf CHg-S0r l CH3 14) O CH O CH3 I OH In general, thenovel compounds of this invention can be prepared by several methods.One such method comprises reacting a tertiary amine, such as pyridine,with a halogen substituted alkyl acetal, such as a compound of theformula:

0 wherein y is an integer of from 1 to 5 inclusive This intermediateproduct is reacted with hydrogen ion, such that the aldehyde derivativeis prepared. This aldehyde compound is reacted in base with anacetophenone such as the compound of the formula:

v l- 3H:

l O CH;

to give rise to a product of the formula:

OCH:

which can then be reduced, such as by hydrogen, to a dialkox \'phenylquaternary ammonium compound,

() OCH;

merrily-Q A-i 11a.x

\V IHCHzh-E) wherein y and z are as previously defined, and X is or CHSO or its ortho dialkoxy equivalent, is reacted with a tertiary amine,as for instance a compound of the formula:

CH; and a. product of the formula:

mcn -o is obtained. Dealkylation of the alkoxy groups prepares thedihydroxy compound, if such is desired.

Compounds containing the optional A group, namely an atom of oxygen orsulfur, and an all hydrocarbon R, are prepared by a slightly differentalkylation process. This is necessary in view of the fact that thedihydroxy compounds cannot be prepared by the aforementioned synthesisin view of the inability of any reagent to differentiate between thealkoxy groups in the 2,5 positions and the alkoxy group that would be inthe 1 position. Therefore, to prepare compounds containing the optionalA, group, an alkoxyalkoxy compound such as the one of the formula 0 CHOICHi-lyH OCHgOlCHzlvH or its ortho equivalent, wherein A, y andzare aspreviously defined, is reacted with a compound such as toluene sulfonylchloride in an organic base such as pyridine to prepare an intennediateof the formula:

oomo cnnyrr which is then reacted with any tertiary amine, such astriethyl amine to yield an end product of the formula:

oonzo orn n Treatment of the above with dilute mineral acid removes thealkoxymethyl groups and prepares the dihydroxy product.

Compounds containing ether or thioether groups in the R unit of LA R-Dare prepared by treating compounds of the following formulas:

OCHzOlCHrlyH y and A are as previously defined, or their orthoequivalents with reagent such as Nal-l in dimethylsulfoxide followed bythe addition of one mole of ethylene oxide or its sulfur counterpart.More than one ether or thioether units can be added to increase the sizeofR" by increasing the number of moles of ethylene oxide or ethylenesulfide added in the addition step. The preferred mode, however, is theunimolar addition followed by a NaH treatment between the additions ofeach mole of ethylene oxide or sulfide. Following the addition of theether units to the starting materials, the same alkylation processes arecarried out as well as same treatment to remove the alkoxymethyl groups.It is, of course, understood that other epoxide units such as propyleneoxide, etc., can be added in like manner.

The removal of the protective alkoxy groups to form the desiredhydroxy-substituted compounds may be accomplished by known hydrolysistechniques A typical dealkylation process involves complexing the groupto be removed with boron tribromide. followed by decomposition of theresulting complex with water. Another dealkylation process comprisestreatment of the methoxy intermediate with aqueous HBr or HBr in aceticacid.

The various reaction conditions. e.g., time, temperature, pressure,selection of solvents to form the reaction mixture, etc., are notcritical to the practice of this invention unless so indicated withinthe confines of this application, and will therefore be readily apparentto the skilled artisan in the light of the foregoing descriptivematerial. The essence of the invention is, therefore, the aforementionedselection ofsteps, in the order described to obtain the desired endproduct, as well as the end product itself.

The invention will be illustrated in greater detail in conjunction withthe following specific examples which set out representativepreparations of the novel compounds of this invention, which, however,are not limited to the details therein set forth and are intended to beillustrative only.

EXAMPLE I Preparation of N-y(2', '-dihydroxyphenyl) propyl pyridiniumbromide.

ln a nitrogen atmosphere, g. of lithium aluminum hydride (M.W. 37.95),0.4 moles, was slurried in 200 cc. of dry ether. 87 g.of2,S-dimethoxydihydrocinnamic acid, 0.416 moles, in 550 cc. of dryether was added dropwise. The addition of the ether caused thedihydrocinnamic acid to reflux without the addition of extra heat.Stirring was continued for a period of 1 hour. Sufficient water wasadded dropwise, to decompose excess lithium aluminum hydride.

620 cc. of 10 percent H 80 were added to the reaction vessel. A twolayer system resulted. The ether layer was separated and washed severaltimes with an aqueous solution of NaH- CO cautiously, and then withwater and dried. The ether was evaporated off leaving a fluid oilcomprising 2,5-dimethoxyphenyl propyl alcohol. 54 g. of theapproximately 70 g. of said alcohol were cooled to 10 C. To this wasadded 40 g. of PBr 0.14 moles dropwise. The temperature was permitted toreach room temperature and the mixture was stirred for 2 hours and thenallowed to stand overnight. It was heated to 80 C. for 0.5 hours andthen cooled and poured onto ice mixed with water. The end product whichwas 2', 5'- dimethoxyphenyl 3-propyl bromide was extracted with ether,washed and dried. 52 g. (0.2 moles) of the bromide and 15.8 g. (0.2moles) of pyridine in 200 cc. of dioxane were heated for 52 hours, withtwo layers being formed. The desired product, a yellow viscous oil, wasseparated and then refluxed overnight in approximately 350 cc. of 48percent HBr, while under nitrogen. The nitrogen blanket was maintaineduntil most of the liquid evaporated. The remainder was cooled andacetone was added. The resulting precipitate was washed in acetone,collected and dried under vacuum. Approximately 16 g. of an orange-tanproduct was obtained. The product was recrystallized from ethanol,melting point 167 C. for analysis. The analysis was in agreement withthe assignment of the structure as N-'y(2', 5'-dihydroxyphenyl)propylpyridinium bromide.

Analysis.Calculated for C H XO BI (percent): Nitrogen,4.52%. Found(percent): Nitrogen, 4.52%.

EXAMPLE II 4-methylquinolinium bromide.

3-( 2', 5' dimethoxyphenyl) propanal, 34.0 g., 0.2 moles, was dissolvedin 400 ml. of percent ethanol. Sodium borohydride, 7.4 g., 0.2 moles,was added and the reaction mixture refluxed two hours. The solvent wasremoved in vacuo and water and ethyl ether were added. The ether extractwas washed with water, dried (anhydrous magnesium sulfate) andconcentrated to a heavy oil. The oil, 27 g., 79 percent, 3-(2',S'dimethoxyphenyl)propanol was used directly. An infrared analysisshowed that no aldehyde remained unreacted.

The 3-(2', 5 dimethoxyphenyl)propanol, 27 g., 0.137 moles, was cooled to10 and phosphorous tribromide 20 g., 0.074 moles, was added dropwisewith stirring. The reaction was allowed to rise to room temperature andwas stirred for an additional two hours and finally heated at 80 forone-half hour. The reaction mixture was poured into ice water and theproduct extracted into ethyl ether. The ether was washed with water anddried. The crude 3-(2, 5-dimethoxyphenyl)propyl bromide was obtained byremoval ofthe ether.

Attempts to purify a sample of the crude product by distillation at 18mm. pressure and a temperature of 155 C. gave a clear liquid which waslargely converted to a methoxy chroman. Because of this sensitivity toheat, the crude product was used directly in the synthesis of thequaternary salt.

The propyl bromide product, 5.6 g., 0.04 moles, and 4- methylquinoline,5.6 g., 0.04 moles, were dissolved in 40 ml. dioxane and heated on thesteam cone two days. On cooling, two layers were obtained. The dioxanelayer was decanted and ethyl ether-ethyl acetate trituration was used toobtain the product. The crude solid was taken up in 60 ml. ofconcentrated hydrobromic acid and the reaction mixture refluxed 2%hours. The HBr was removed by evaporation on the steam cone using anitrogen stream. Trituration of the residue with acetone gave 2 g. ofN--y(2', 5-dihydroxyphenyl)propyl-4"- methylquinolinium bromide whichwas crystallized from ethanol, m.p. 238-9.

The photographic utilization of the novel compounds of this inventionwill be illustrated in greater detail in conjunction with the followingspecific examples which set forth representative processes and which arenot intended to be limiting, but are meant to be illustrative only.

EXAMPLE III A photosensitive element was prepared by coating a gelatinsubcoated film base at a speed of 15 feet per minute with a solutioncomprising 2 g. ofa compound ofthe formula:

I O H comprising:

Water cc. NaOh 5 g.

Hydroxyethyl cellulose Benzotriazole 1 g.

After an imbibition period of approximately 1 minute. the spreaderelement was separated and it was found that a good negative image waspresent in the photosensitive element ln the following example. thenovel compounds of this invention are utilized in a diffusion transferprocess wherein unreduced (i.e., the hydroquinone form) quaternaryammonium developing agent is transferred by imbibition to animagereceiving layer and upon aerial oxidation, e.g., by oxygen in theair upon separation of the image-receiving layer from the photosensitiveelement, is caused to undergo an oxidative coupling with a secondmolecule of the quaternary ammonium developing agent. ln this reaction,an active methylene group present on the QUAT portion of one moleculecouples to the quinonyl portion of an oxidized DEV-LlNKQUAT molecule,whereby a colored immobile polymeric" compound is formed in theimage-receiving element in the areas corresponding to the undevelopedareas of the photosensitive element. Such a transfer process forms thesubject matter of a copending application Ser. No. 741,548 in the nameof Stanley M. Bloom herewith, now US. Pat. No. 3,537,852. It is to beunderstood that not all compounds of the formula DEV- LlNK-QUAT arecapable of participating in an oxidative reaction of this nature. Onlythe compounds which are capable of generating an enamine can soparticipate and then only if the pH has been adjusted to facilitate theself coupling reactton.

EXAMPLE lV A photosensitive element was prepared by coating a gelatinsubcoated film base at a speed of feet per minute with a solutioncomprising 1 g. ofa compound of the formula:

which was dissolved in 100 cc. of a solution containing 5.0 g. celluloseacetate hydrogen phthalate in a 1:1 mixture, by volume, ofmethoxyethanol and ethanol. After this coating dried, a blue-sensitivesilver iodobromide emulsion was coated thereupon at a speed of 10 feetper minute and allowed to dry. This photosensitive element was exposedand processed by spreading an aqueous processing composition between thethus exposed photosensitive element and a superposed imagereceivingelement, said aqueous processing composition comprising:

Water 100cc.

NaOH 5g.

EXAMPLE V Utilizing a pair of standard iodobromide panchromaticsensitized negatives, the compound was tested as a developing agentagainst 4-methylphenylhydroquinone, a control developing agent whosedeveloping characteristics are well known in a diffusion transferprocess.

The processing compositions utilized comprised 100 cc. of water to whichwas added 3.8 g. of hydroxyethyl cellulose. 11.2 g. of per cent pureKOH, 0.93 g. of the test compound and 0.6 g. of 4-methylphenylhydroquinone. respectively. In duplicate tests, the negatives areexposed under conditions so that one-half of each negative is totallyunexposed and the other half of the negative is totally exposed. Thethus exposed negative and an image-receiving element are brought intosuperposed relationship and the processing composition is spreadtherebetween as the exposed negative and the imagereceiving element areadvanced at a constant rate between a pair of rollers. The resultingsandwich is scanned by infrared light. All the components of thesandwich are transparent to infrared light except for silver formed bydevelopment. It is to be noted that no silver is deposited on thereceiving layer by diffusion transfer since a silver solvent is notpresent in the processing compositions. The reduction in infraredtransmission due to silver formation as a function of imbibition time isreproduced electronically as a trace on a time and density grid on anoscilloscope tube, and the resulting oscilloscope tracing isphotographed. The'upper line in each such oscilloscope tracingrepresents the initiation of the development of exposed silver halideand the amount of silver developed in a given time in the fully exposedareas of the negative. The lower line represents the initiation of thedevelopment of unexposed silver halide in the totally unexposed areas ofthe negative and the amount of unexposed silver halide developed andtherefore is a direct representation of the amount of fog development.The results of this test indicating the difference in fog buildup by thetwo developing agents are set forth graphically below:

It is seen that the test compound is a better discriminatory developer,i.e., the delta density difference between exposed and unexposed areaswas greater with the test compound that with the 4'-methylphenylhydroquinone.

The compounds of the present invention can also be utilized asmordanting developing agents in accordance with the concepts of thenovel image forming process of Howard C. Haas, the subject matter ofwhich is found in copending application Ser. No. 740,965, filed June 28,1968, now abandoned. The following nonlimiting example is incorporatedherein from said copending application to illustrate the utilization ofthe compounds of the present invention as silver halide developingagents which will interact with gelatin when they are oxidized to formin the photosensitive emulsion an imagewise distribution ofa mordant fora negatively charged dye, such as an acid dye. When such a dye isassociated with the instant compounds, it is mordanted in place in thedeveloped areas of the photosensitive emulsion where it is free totransfer from the undeveloped areas to form a transfer image.

EXAMPLE VI A photosensitive element was prepared as follows: 3.75 g. ofC.I. 15080 Direct Red 3, Benzo Brilliant Geranine B, of the formula:

SOsNa was dissolved in 45 cc. of water. This solution was emulsified bymeans ofa high shear mechanical agitator, with an aqueous solution of g.of IO percent gelatin, to obtain a uniformly blended mixture. 50 cc. ofthe resulting dye dispersion were mixed with 78 cc. of water and thencoated upon a subcoated film base. After this coating dried, ablue-sensitive silver iodobromide emulsion was coated thereupon at acoverage of 317.9 mg. per square foot of silver and allowed to dry. Thisphotosensitive element was exposed and processed by spreading, betweenthe thus exposed photosensitive element and a superposed image-receivingelement, an aqueous processing composition comprising:

Water 90g.

NaOh 4g.

Hydroxyethyl cellulose 3g.

N-y(2', 5'-dihydroxyphenyl) propyl-pyredinium bromide 3g. Theimage-receiving element comprised baryta paper coated with a layer of a2:1 mixture, by weight, of polyvinyl alcohol and polyA-vinyl-pyridine.After an imbibition period of ap proximately one minute, theimage-receiving element was separated and contained a red-positiveimage.

From the examples above, it is evident that the compounds of the presentinvention have particular utility as silver halide developing agents indiffusion transfer processes. both dye and silver.

It will be apparent that the relative proportions of developing agentsand other ingredients and materials illustrated in the above examplesmay be varied to suit the requirements of one skilled in the art. Thus,it is within the scope of this invention to substitute alkalies otherthan sodium hydroxide in the processing composition. Likewise, it isalso contemplated that where desirable the processing or developingcompositions may be modified by the inclusion of other common componentsof developer compositions such as restrainers, preservatives,accelerators, etc. Where the processing compositions are to be employedin silver diffusion transfer processes, they may have incorporated inthem as a further ingredient a silver halide solvent such as sodiumthiosulfate. if the processing composition is to be applied to theemulsion by being spread thereon in a thin layer, it may also include afilmforming thickening agent such, for example, as a high molecularweight polymer, e.g., hydroxyethyl cellulose or sodium carboxymethylcellulose. Thus, by adding sodium thiosulfate to the pertinentcompositions, e.g., Example In, illustrated above and using animagereceiving layer containing silver precipitating agents as is wellknown in the art, in conjunction with the photosensitive element, asilver transfer image may be obtained.

It will be apparent that, by appropriate selection of the support andcoatings forming the image-receiving element from among suitable knownopaque and transparent materials, it is possible to obtain either apositive reflection print or a positive transparency.

As examples ofuseful color image-receiving materials, mention may bemade of nylon, e.g,, N-methoxymethyl-polyhexamethylene adipamide,polyvinyl alcohol, and gelatin, particularly polyvinyl alcohol orgelatin containing a dye mordant such as poly-4-vinylpyridine.

The utility of the compounds of this invention is by no means limited todiffusion transfer processes for they may be satsifactorily employed inconventional multistage multibath photographic processes inblack-andwhite or color photography. A typical developer compositionwould include in addition to a compound of this invention, ingredientsas sodium hydroxide, sodium sulfite and potassium bromide. Afterdevelopment is completed, any unreacted developing agent is washed outof the photosensitive element preferably with an alkaline washing mediumor other medium in which unreacted developing agent is soluble.

In the preceding portions of the specification, the expression color hasbeen used. This expression is intended to include the use ofa pluralityol'colors to obtain black.

Since certain changes may be made in the above products and processesand compositions without departing from the scope of the inventionherein involved, it is intended that all matter contained in the abovedescription shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. In a diffusion transfer process which comprises the steps ofdeveloping an exposed silver halide emulsion with an aqueous alkalinesolution of a silver halide developing agent, forming an imagewisedistribution of a diffusible image-forming component, and transferringat least a portion of said imagewise distribution of said image-formingcomponent by diffusion in alkaline solution to an image-receiving layerto provide a transfer image, the improvement which comprises saidprocess in the presence of at least one compound selected from thoserepresented by the formula:

L-A,,-R-D wherein L is an unsubstituted, alkylsubstituted or halogensubstituted monovalent radical selected from the group consisting ofphenyl and naphthyl rings substituted in ortho or para positions withrespect to each other by .A--OH and ANH at least one of said positionsbeing substituted by A--OH;

A is selected from the group consisting of oxygen and sulfur;

e is 1 or 0; R is a divalent radical of the formula:

2l 2 4]ml 2]" z wherein m is a number from 0 to 4 inclusive; n is anumber from O to 8 inclusive; the sum of m+n being not greater than 8;

D is a cyclic, acyclic, or part cyclic part acyclic quaternary ammoniumradical selected from the group of radicals of the formulae:

wherein each Q and T are acyclic hydrocarbon or halogen substitutedhydrocarbon groups, M represents the atoms necessary to complete aheterocyclic ring and may contain in addition to carbon and hydrogenatoms, an atom selected from the group consisting of nitrogen, oxygen,sulfur and selenium, and X is an anion selected from the groupconsisting of halide, methyl sulfonate and p-toluenesulfonate.

2. (Amended) The process of claim 1, the step which comprises conductingsaid process in the presence of at least one compound selected fromthose represented by the formulae:

OH and wherein z is an integer of from 2 to 10 inclusive, and A isselected from the group consisting of oxygen and sulfur; and

D is a cyclic, acyclic or part cyclic part acyclic quaternary ammoniumradical selected from the group of radicals of the formulact whereineach and T are acyclic hydrocarbon or halogen substituted hydrocarbongroups, M represents the atoms necessary to complete a heterocyclic ringand may contain in addition to carbon and hydrogen atoms, an atomselected from the group consisting of nitrogen, oxygen, sulfur andselenium, and X is an anion selected from the group consisting ofhalide, methyl sulfonate and p-toluenesulfonate.

3. The process as defined in claim 1 wherein the compound represented bythe formula:

lA -R-D is selected from the group consisting of N-'y(2',dihydroxyphenyl) propylpyridinium bromide, N- 'y( 2 5 -dihydroxyphenyl)propyl-2"- methyliquinolinium bromide and N- 'y(2', 5'-dihydroxyphenyl)propyl- 4"-methyliquinolinium bromide.

4. The process of developing a latent image in a silver halide emulsionwhich comprises treating said emulsion with an aqueous alkaline solutionin the presence of a compound selected from those represented by theformula:

LARD wherein L is an unsubstituted, alkylsubstituted or halogensubstituted monovalent radical selected from the group consisting ofphenyl and naphthyl rings substituted in ortho or para positions withrespect to each other by AOH and A-NH at least one of said positionsbeing substituted by AOH;

A is selected from the group consisting of oxygen and sulfur;

e is 1 or 0; R is a divalent radical of the formula:CH

[ 2 ]m' 2in z 2[ 2 4]m z ],,CH, wherein m is a number from 0 to 4inclusive; n is a number from 0 to 8 inclusive; the sum ofm n being notgreater than 8;

D is a cyclic, acyclic, or part cyclic part acyclic quaternary ammoniumradical selected from the group of radicals of the formulae:

r X- k." T

and

formulae:

wherein each 0 and T are acyclic hydrocarbon or halogen substitutedhydrocarbon groups, M represents the atoms necessary to complete aheterocyclic ring and may contain in addition to carbon and hydrogenatoms, an atom selected from the group consisting of nitrogen, oxygen,sulfur and selenium, and X is an anion selected from the groupconsisting of halide, methyl sulfonate and p-toluenesulfonate.

6. A process of developing a latent image in a silver halide emulsionwhich comprises treating said emulsion with an aqueous alkaline solutionin the presence of a compound selected from the group consisting of N-y(2, 5'-dihydroxyphenyl) propyl-pyridinium bromide, N-'y( 2,5'-dihydroxyphenyl) propyl-4- methylquinolinium bromide and N- 'y(2',5-dihydroxyphenyl)propyl-2-methylquinolinium bromide.

7. (Amended) A photographic product comprising a plurality of layers, atleast one of said layers including a silver halide emulsion, and atleast one of said layers including a compound selected from those of theformulae:

and

I OH

wherein z is an integer of from 2' to 10 inclusive, and A is selectedfrom the group consisting of oxygen and sulfur;

D is a cyclic, acyclic or part cyclic part acyclic quaternary ammoniumradical selected from the group of radicals of the formulae:

wherein each and T are acyclic hydrocarbon or halogen substitutedhydrocarbon groups, M represents the atoms UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent 3,590 .692 Dated 11111;, 6 1q71 InV8nt0Stanley M B'lnmn It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

IN THE CLAIMS:

Claim 1, line 14, after "comprises" insert "conducting".

Claim 1, line 21, -oH" should read Claim 1, line 21, "A-NH should read"--NH Claim 1, line 22, "AOH" should read OH" Claim 4, line 41, "AOH"should read "OH" Claim 4 line 41, "ANH should read "-NH Claim 4, line42, "AOH" should read "OH" Claim 4, lines 44-46, the formulae shouldread:

Signed and sealed this 27th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Atteating Officer- Commissionerof Patents FORM r c-1050 (10-69) uscoMM-Dc norm-P60 Q I.I.S GOVIINIIINYPIINTHG OFFICE II" O-ll-IJI

2. (Amended) The process of claim 1, the step which comprises conducting said process in the presence of at least one compound selected from those represented by the formulae:
 3. The process as defined in claim 1 wherein the compound represented by the formula: 1-Ae-R-D is selected from the group consisting of N- gamma (2'', 5 '' dihydroxyphenyl) propyl- pyridinium bromide, N- gamma ( 2 '', 5 ''-dihydroxyphenyl) propyl-2''''-methyliquinolinium bromide and N- gamma (2'', 5''-dihydroxyphenyl) propyl- 4''''-methyliquinolinium bromide.
 4. The process of developing a latent image in a silver halide emulsion which comprises treating said emulsion with an aqueous alkaline solution in the presence of a compound selected from those represented by the formula: L-A-R-D wherein L is an unsubstituted, alkylsubstituted or halogen substituted monovalent radical selected from the group consisting of phenyl and naphthyl rings substituted in ortho or para positions with respect to each other by Delta -OH and Delta -NH2, at least one of said positions being substituted by Delta -OH; A is selected from the group consisting of oxygen and sulfur; e is 1 or 0; R is a divalent radical of the formula:-CH2 (OC2H4m-(CH2n -CH2-or -CH2(SC2H4m -(CHz n-CH2 -wherein m is a number from 0 to 4 inclusive; n is a number from 0 to 8 inclusive; the sum of m + n being not greater than 8; D is a cyclic, acyclic, or part cyclic part acyclic quaternary ammonium radical selected from the group of radicals of the formulae:
 5. (Amended) The process of developing a latent image as in claim 4 which comprises treating said emulsion with a compound selected from those represented by the formulae:
 6. A process of developing a latent image in a silver halide emulsion which comprises treating said emulsion with an aqueous alkaline solution in the presence of a compound selected from the group consisting of N- gamma (2'', 5''-dihydroxyphenyl) propyl-pyridinium bromide, N- gamma ( 2'', 5''-dihydroxyphenyl) propyl-4-methylquinolinium bromide and N- gamma (2'', 5''-dihydroxyphenyl)propyl-2-methylquinolinium bromide.
 7. (Amended) A photographic product comprising a plurality of layers, at least one of said layers including a silver halide emulsion, and at least one of said layers including a compound selected from those of the formulae:
 8. A photographic product comprising a plurality of layers, at least one of said layers including a silver halide emulsion, and at least one of said layers including a compound selected from the group consisting of N- gamma (2'', 5''-dihydroxyphenyl)propyl-pyridinium bromide, N- gamma (2'',5''-dihydroxyphenyl)propyl-4-methylquinolinium bromide and N- gamma (2'', 5''-dihydroxyphenyl) propyl-2-methylquinolinium bromide. 